The present invention relates to container structures and more particularly to a spill proof container used for comestibles or the like, wherein the comestibles or foodstuffs in the container may be in a liquid or semi-liquid condition. The container of the instant invention in its various embodiments is especially useful in the merchandizing of fast and convenience type food products including in particular food products designated as carryout type foods. In the fast and convenience food industry product costs, speed of assembly, ruggedness and resistance to abuse, ease of handling, reclosure and reuse are all highly desirable characteristics of acceptable containers.
In more recent times the public is also requiring that at least the bottom or tray portion of the container be "dual oven heatable" i.e. the purchaser-user wants to be able to heat the container tray and its contents in either a conventional or a microwave oven regardless of the size, shape or internal configuration of the tray. In other words the tray material preferably should be a microwave penetrable polymeric plastic material.
Prior art containers of the type under consideration are represented by various patents as follows: U.S. Pat. Nos. 1,926,240; 2,490,076; 3,066,824; 3,101,864; 3,246,786; 3,447,714; and 4,412,630, as well as design U.S. Pat. Nos. D. 215,413; D. 223,144; D. 246,289; D. 263,798; D. 276,216; and D. 282,245.
The pertinent prior art containers as disclosed in the aforesaid patent art are not completely acceptable to today's purchasing public for various reasons. For example, the container closure of U.S. Pat. No. 3,066,824 relies on the use of a separate implement such as a knife blade to obtain a complete and full release of the container lid from the tray, while the snap-on container cover of U.S. Pat. No. 3,101,864 is snap locked to its associated tray for the full periphery of each. This makes the initial and the subsequent full release of lid and tray in such a container structure without spillage very problematical. In fact such a locking scheme allows little or no room or tolerance for container distortion during handling, filling or opening without breaking the seal between container parts and increasing the possibility of spillage.
This lack of distortion acceptance without spillage, etc., also appears to be a drawback in the case of the container of U.S. Pat. No. 3,447,714 wherein in the case of a multi-sided or polygonal-type container body, the snap-on locking of the body cover or lid occurs, if at all, along the full length of the several sides rather than at selected points, e.g. the corners. The lid corners also are equipped with special stacking shoulders that could interfere with the normal lid release and opening. Such features, plus the lack of a spillage barrier or splashguard type wall on the cover, not only make such a container difficult to open but also enhance the chance of spillage and lack of fluid food control upon lid and tray release.
The continuous peripheral snap-on lid feature of U.S. Pat. No. D. 276,216 likewise poses spillage problems for liquid and semi-liquid foodstuffs during opening of the container. Carry out containers, because of the nature of the business in which they are used, must be as spill-proof and splash-proof as possible in order to find full acceptability.
Other examples of prior art plastic containers having snap-on lids but not full spill or leak proof properties and over which the instant container structure is an improvement are to be found in Kaiser Aluminum & Chemical Corporation's Advertising Brochure of 1985 and identified by Brochure Number PB-626 8M 10-85.